Soft tissue sarcomas (STS) are a heterogeneous group of malignant tumors that arise from mesenchymal tissues including fibrous connective tissue, cartilage, blood vessels, muscles, nerves, or fat. In the United States, it is estimated that some 11,280 new cases were diagnosed, and 3900 patients died of STS in the year 2012 [1]. The mainstay of local treatment is to completely excise the tumor with a margin of normal tissue so that no malignant cells remain in the tumor bed. The presence of residual sarcoma cells in the tumor bed is associated with local recurrence, which reduces patient survival rates [2-4]. For patients with residual tumor cells at the margin of the resected tumor, re-excision and/or postoperative radiation is required. Such additional therapies increase patient morbidity and healthcare costs.
It has been shown that the presence of cancer cells within the margin of resected specimens is strongly correlated with the risk of local tumor recurrence. Margins therefore play a key role in the prognosis of patients with respect to local recurrence and are directly correlated to the success of surgeries. Consequently, there is a need for intraoperative evaluation of the resection front so that immediate re-excision of suspicious margins can be performed.
Resected specimens differ in shape, size and firmness. Depending on the size and stage of the tumor, the resected specimen can vary in shape and size. The firmness of resected specimen is sometime related to age and body mass index of the patient. This variation in size, sharp and firmness makes the measurement of the specimen surface difficult.
In addition, there is no universal definition of a safe margin (i.e., the thickness of healthy tissue surrounding the tumor). Depending on the organ's location, the size of the safe surgical margin is defined differently. In fact, 2 mm is the safe margin widely accepted by breast surgeons. But most urological surgeons will define the safe margin as the absence of tumor at the surface of the removed prostate specimen. Accordingly, the safe margin should be no more than 0.05 mm in this case.
Generally, any method used to evaluate the surgical margins of a resected specimen must be precise, rapid and relatively simple to implement in order to be used in routine clinical care. The method should be able to scan the entire surface of specimens despite their differences in shape and size; and measure the sample surface while leaving it intact, thus minimizing the physical change of the margin status due to pressure. Furthermore, the method should be able to be applied for a wide range of surgery types for example breast, skin, and prostate cancer surgeries. Besides a precise diagnose of margin status, the method should also provide exact locations of the positive margin (if any are found) in a manner that the surgeon can easily recognize and correctly remove more tissues.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.